1. Field of the Invention
The cultivation of mushrooms has a venerable history. While mushrooms grow readily in the natural state, where they find a supportive environment, efforts to cultivate mushrooms require great care in order to obtain an economic crop. In producing cultivated mushrooms, a substrate must be provided which encourages the growth of the desired mushroom, while discouraging the invasion of undesirable bacteria and fungi. Mushrooms are particularly suspectible to variations in their environment and their growth can be substantially inhibited where the environment does not provide the necessary degree of moisture and aeration.
A mushroom which has long been cultivated in the Orient is the Shiitake mushroom. Its cultivation has depended on the use of logs which are inoculated with spawn and then allowed to grow. Normally, there is a long period, substantially exceeding one year before the first crop can be obtained. Great care must be taken in the growth of the Shiitake mushroom, usually employing a natural environment, so that the environment in which the Shiitake mushroom can be grown is limited.
Since the edible mushroom is an excellent source of food values, there is an increasing interest in enhancing the ability to grow mushrooms in an economical manner. Furthermore the mushroom is primarily grown on waste materials, and thus mushroom cultivation provides a method for turning waste materials into a human food. Finally, the substrate or compost employed after mushroom growth is exhausted, can be employed for mulching or composting crops.
In developing new techniques for growing mushrooms, it is desirable to use readily available inexpensive substrate materials. In addition, such cultivating techniques should provide as rapid a period as possible between the initial inoculation and the harvesting of a crop. Furthermore, it is desirable to maximize the number of crops obtained for each inoculated substrate. There is the additional consideration of the size, quality and yield of the mushrooms.
2. Description of the Prior Art
Texts of interest are Singer, Mushrooms and Truffles, Interscience Publishers, Inc., New York (1961) and Gray, The Use of Fungi as Food and in Food Processing, CRC Press, Cleveland, Ohio (1970). U.S. Pats. of interest include U.S. Pat. Nos. 1,832,593; 1,833,089; 2,005,365; 2,677,917; 2,761,246; and 3,560,190. Foreign patents of interest include UK Patent No. 462,316; French Pat. No. 1,445,649 and Japanese Pat. Nos. 8756/64; 16050/70; 27768/70; 28527/70; 28532/70; 37047/70; 25682/71; 22768/72; 42660/72; and 3334/74;